Apparatus for opening and closing the transverse sealing jaws of a packaging machine



March 9, 1965 Filed March 22, 1963 J. F. AQUARIUS ETAL APPARATUS FOR OPENING AND CLOSING THE TRANSVERSE SEALING JAWS OF A PACKAGING MACHINE 2 Sheets-Sheet l Fig.2

/N VE N TOPS JonuMA-s FT AQUARIUS THEOD oRu: H. AQ an R1 us Jon/was v. a. Fun/051v gnaw-a4 1 March 1965 J. F. AQUARIUS ETAL 3,172,245.

APPARATUS FOR OPENING AND CLOSING THE TRANSVERSE SEALING JAWS OF A PACKAGING MACHINE Filed March 22, 1965 2 Sheets-Sheet 2 VIII/111111111.

ll i g ubg INVENTORS United States Patent 3 172,245 APPARATUS FOR OPENING AND CLOSING THE SVERSE SEALING JAWS OF A PAQIKAGENG MACHINE Joannes Franeiscus Aquarius, St. Josephlaan 225; Theodorus Hubertus Aquarius, Victor de Stuerstraat 36; and Joannes van den Eijnden, Graaf-Jacohtraat 24, all of Weert, Netherlands Fiied Mar. 22, 1963, Ser. No. 267,297 Claims priority, application Germany, Aug. 25, 19-62, A 41,019 8 Claims. (Cl. 53-182) This invention relates to an apparatus for opening and closing the transverse sealing jaws of packaging machines of the type which produce individual filled and sealed packages from a tube of heat-sealable material.

Packaging machines of this type are well known. Usually the heat-sealable packaging material is supplied in the form of a continuous web wound upon a supply roll. The web is led from the supply roll around a forming element which serves to convert the initially flat web into a tube with the longitudinal edges of the tube in overlapping relationship. In this condition, the tube surrounds a filling pipe of the machine, and a heated tool cooperates with the filling pipe to fuse the longitudinal edges of the web. Beneath the forming element and filling pipe an apparatus is provided comprising a pair of transverse sealing jaws arranged on opposite sides of the tubular packaging material, the jaws being mounted for movement toward each other to produce a transverse seal in the tubular material. This operation produces an upper seal on the package that has already been filled, and a lower seal for the next package to be filled. The apparatus also provides means for severing the tube between these transverse seals. Additionally, while the jaws are in engagement with the tubular material clamped between them, they move in a direction parallel to the longitudinal axis of the tube in order to advance the packaging material through the machine. After the jaws separate, they move back in the direction opposite to the direction of advancement of the packaging material to their initial position, preparatory to the formation of the next transverse seal.

Thus it is apparent that in machines of this type the apparatus must provide for two kinds of jaw movement. Not only do the jaws move toward and away from each other in a direction transverse to the tubular packaging material, but they also move lengthwise back and forth in an up-and-down direction. Substantial forces are involved with each type of movement, because a large sealing pressure is desirable when the jaws are brought together, and during the downward longitudinal movement of the jaws a pulling force must be exerted which is sufficient to draw the supply material over, and downwardly from, the forming element.

In machines heretofore known, the actuation of the sealing jaws is brought about by mechanical means, and it is apparent that the mechanisms must necessarily be rather complicated because of the two types of movements, and the substantial forces, that are required. As a result, the mechanisms are easily susceptible to malfunctioning and impairment, and additionally they produce considerable noise during the functioning of the machine. Moreover, such mechanisms impose severe limitations upon the speeds at which the machine may function.

One of the objectives of the present invention is to provide an apparatus which is devoid of these, and other, disadvantages, which is unusually simple in nature and mode of operation, and which is better adapted to create and withstand the relatively large forces that are involved. Additionally, the improved apparatus provides a means 3,172,245 Patented Mar. 9, 1965 ice for readily adjusting the pressure exerted by the jaws when they come together. The improved apparatus affords an efficiently enclosed and compact construction that requires a minimum of servicing and has almost no parts that are likely to wear out.

Another objective is to provide an apparatus that is better able to withstand the sudden stoppages that are involved when the machine is involved in producing packages from material that has previously been imprinted. In such cases, appropriate photo-electric devices are provided to control the advancement of the packaging material in such a way that the printed markings lie in proper predetermined relationships to the resultant packages. Among the systems employed for this purpose are the following:

(a) From the forming element a length of packaging material is pulled which is longer than that of the next package to be formed. Thereupon, after the transverse sealing jaws have separated, the tubular material is pulled back until an appropriate sensing device responds to a predetermined marking on the tube. The movement of the tube is then brought to a halt by mechanism responsive to this sensing device;

(12) The downward movement of the packaging tube, as it is pulled by the closed sealing jaws, is discontinued in direct response to a sensing device when a predetermined marking reaches a point that brings the sensing device into action; and

(c) The downward stroke of the jaws is somewhat longer than that of the next jackage to be formed. As soon as the sensing device is brought into action by a predetermined marking on the tube, the jaws are caused to open so that during the further downward movement of the jaws they do not carry the tubular material with them any further.

The suddenness of operation of the jaw-controlling mechanism especially in cases (b) and (c), and the sudden stoppages that are involved, make it essential for the apparatus to be unusually rugged.

To achieve the objectives of the invention, the improved apparatus is characterized by the provision of at least one hydraulic cylinder-piston arrangement mounted so that the cylinder and piston may move in a direction transverse to the axis of the tubular packaging material, the cylinder being secured to one of the transverse sealing jaws and the piston to the other. The actuation of the cylinder-piston device is brought about in two stages, the first stage being controlled by a suction-and-pressure pump actuated from the main drive shaft of the packaging machine, the second stage being controlled by a second pump, also driven by the main shaft of the machine, and adapted to introduce additional fluid under pressure.

Further details of the invention will become apparent from a consideration of the following description of an illustrative embodiment of the invention, in which reference is made to the accompanying drawings.

In the drawings:

, FIG. 1 is a schematic representation of a packaging machine of the type to which this invention relates;

FIG. 2 is an enlarged representation of the sealing jaws shown in FIG. 1 and designated by the reference character K;

FIG. 3 is a cross-sectional view along the line III-.III of FIG. 1, showing the apparatus for controlling the operation of the transverse sealing jaws; and

FIG. 4 is a diagrammatic representation of apparatus by means of which the illustrative cylinder-piston arrangement shown in FIG. 3 is actuated and controlled.

The packaging machine schematically represented in FIG. 1 is of a conventional type. A housing 1 is provided at its top with a plate 2 mounted in cantilevered the filling tube 3 concentrically therewith. The heat scalable packaging material, in the form of a continuous sheet or web, is drawn from the rear of the machine where it is supported on 'a suitable supply roll 5. The

, web is pulled from this supply roll, passes over theguide roller 6, thence over the forming element 4 which causes the web to assume a tubular condition surrounding the filling pipe 3, with the longitudinal edges of the web in overlapping relation. A longitudinally arranged heated sealing tool '7' cooperates with the forming tube 3 for intermittenty heat-sealing successive portionsof the overlapping longitudinal edges, thereby producing a continuous tube.

Beneath the tube 3 there are two heated sealing jaws 8 and 9, mounted for movement toward and away from each other in the direction of the double-headed arrows. Additionally, these transverse sealing jaws are movable vertically in a manner hereinafter to be described in greater detail.

When the jaws 8 and 9 move into engagement with each other, as best shown in FIG. 2, they clamp the tubular packaging material between them, and as a result the lower regions e and c produce the upper transverse heat seal on the package previously filled, while the upper regions f and f form the lower transverse seal on the next package to be filled and formed. Simultaneously with the production of these transverse seals, the jaws 8 and 9 move downwardly and thus pull the tubular material from the supply roll 5 over the guide roll 6 and the forming element 4. During this period the tubular material is severed between the two seams by a cutting device 12, which may be a knife having a serrated edge as indicated in FIG. 3'. Preferably the jaw 9 has a recess 60 (FIG. 3) into which the cutting edge of the knife extends during the cutting operation.

When the jaws reach the lower end of their longitudinal movement and separate, or, when they separate in response to a sensing device activated by an appropriate predetermined marking on the tube, the filled and sealed package at the bottom, whicl1 has by now been severed from the remainder of the tube, falls away. In

open or separated condition, the jaws travel back, in the direction opposite to the direction of advancement of the tubular material, to the upper end of their longitudinal movement. During this period, a measured charge of the product to be packaged. is discharged from the filling apparatus and falls. through the filling pipe 3 into the tubular material, the bottom end ofwhich has been sealed. After the jaws 3 and 9 have reached the upper end of their movement, and after the introduction of the fresh charge of the product, the jaws come together again and the process of producing transverse seals and again pulling the tube downwardly to advance the web is repeated.

The details of the apparatus for controlling the horizontal or transverse actuation of the sealing jaws are illustrated in FIGS. 3 and 4. The means for moving the jaws longitudinally in the direction of the tube axis has not been illustrated since any known kind of mechanism for, accomplishing this may be employed. Suitably mounted in the framework of the machine is a vertically reciprocable post 13, to which a transverse double-armed yoke 14 is secured. At each of the opposite ends of the yoke 14 there is a cylindrical bearing 15, and in each bearing a tubular element 16 is slidably mounted for longitudinal movement. The tubular elements 16 are connected at their forward ends by the transversely extending element 17 which also serves as a support for the sealing jaw 9. The jaw 9 is secured to and moves with the crosspiece 17.

At its rear end, each tubular element 16 is connected to an hydraulic cylindrical 18 in coaxial relation thereto. A cooperating piston 19 is slidably mounted in each cylinder 18, and the piston rod 21 extending from it is slidably axially within the element 16. At their forward ends 25, the piston rods 29' are connected by the transverse elernent 24. This securement may be achieved, for example, by the nuts" 26 threaded onto the ends of the rods 20. At its midportion, the element 24 carries the cuttingknife 12, which is mounted so as to project toward the recess 64) in the jaw 9.

Between the cros'spieces 17 and 24 is a pair of compression springs 27 constantly urging the parts 17 and 24 into separated relationship. This action of the springs 27 is limited by the enlargements 28 formed on the pistonrods 20 and lying within the cylinders 18, respectively. These enlargements abut the floors of their respective cylinders, thus limiting the extent of separation between the parts 17 and 24, and the jaws and other elements which these parts carry.

In the regions surrounding the end of each rod 20, the crosspiece 24 is formed with a boss 23. The transverse sealing jaw 8 is formed with cylindrical ends that fit over the bosses 23, respectively, and are slidable thereon. The internal diameters of these cylindrical parts are larger than the rods 20, and compression springs 22 are mounted in the spaces thus afforded. One end of each spring 22 bears against the boss 23, thus serving constantly to urge the jaw 8 in the direction of the other jaw 9. The extent of this movement is limited by the flange 21 formed on each rod 20, the'jaw S'bea'ring against these flanges under the influence of the springs 22. The movement of the jaw S in the opposite direction is limited by the abutment of the cylindrical par-ts against the crosspiece 24, the total extent of movement being indicated by the reference letter h.

Communicating with each cylinder 18,. in the region behind the piston 19, is a pipe 38 through which fluid under pressure can be introduced and withdrawn for the purpose of actuating the jaws 8 and 9. The means for introducing and withdrawing the pressurized fluid is shown in FIG. 4-.

Referring now to FIG 4, the main drive shaft of the packaging machine is indicated at 31. Rigidly secured on this shaft, in predetermined relative angular settings, are eccentrics or cams 32, 56 and 54. The cam32 cooperates with a follower roller 33 mounted on a spindle 35 in the outer end of a plunger 34. This plunger is longitudinally slidable within a cylinder 36, and is constantly urged toward the cam 32 by the compression spring 37 within the cylinder. The interior of the cylinder 36' communicates, through a conduit 39, with a supply of fluid under pressure, diagrammatically indicated at 38. A one-way valve 40 in the conduit 39 operates to allow fluid to flow only in the direction from the fluid supply 38 to the interior of the cylinder 36. A similar one-way valve 41 is mounted in the conduit 42, leading to the pipes 30, for preventing flow of fluid under pressure from the conduit 42 into the interior of the cylinder 36. Between the one-way valves 40 and 41, a pressure-relief valve 43 is mounted, the latter valve being normally held closed by the compression spring 44, the strength of which will be described more fully hereinafter.

The cam 56 on the shaft 31 cooperates with and bears against a plunger 45 mounted for sliding movement within a cylinder 47, a compression spring 46 serving to urge the plunger 45 against the cam 56. The cylinder 47 is in communication with the conduit 42 on the side of the valve 41 remote from the cylinder 36. The cam 54 on the main shaft 31 cooperates with a control valve 52 mounted within a conduit 53 which extends from the fluid supply 33 to the conduit 42. The conduit 42 also communicates, through pipe 51, with the fluid supply 38. Arranged in the conduit 51 is an excess-pressure valve 48 normally held in closed position by one arm of a bellcrank lever 49, the other arm of the lever being constantly urged into the position shown in FIG. 4 by a tension spring 50. The strength of this spring will be described more fully hereinafter. Additionally, the end of the bellcrank lever 49 connected to the spring 50 is articulated to the armature of an electromagnet or solenoid 55. The current flow in the solenoid 55 is controlled by a sensing apparatus (not shown) which responds to predetermined markings on the tube of pack aging material as the latter moves through the machine.

The operation is as follows: During rotation of the main shaft 31, the piston or plunger 34 moves back and forth within the cylinder 36. As a result, fluid is withdrawn from the supply 38 through the conduit 39 and then pumped through valve 41, conduit 42, and pipes 30 into the cylinders 18. As a result, the pistons 19 move toward the right (as viewed in FIG. 3) while the cylinders 18 slide toward the left through the bearings 15. The movement of the pistons 19 and cylinders 18 causes the jaws 8 and 9 to move toward each other against the force of the springs 27. A synchronizing mechanism (not shown) serves to equalize the extent of movement of the cylinders 18 in one direction with the extent of movement of the pistons 19 in the opposite direction so that the jaws 8 and 9 come together directly beneath the pipe 3. The movement of the cylinders 18 and pistons 19 in opposite directions reduces to a minimum the amount of shock transmitted to the framework of the machine, thus making the operation quieter and permitting the apparatus to be lighter in weight.

In order to assure a reliable cooperative meeting of the jaws 8 and 9, despite possible temporary deficiencies in fluid pressure, the parts are so designed that the plunger 34 delivers more fluid than the cylinders 18 can accommodate. As a result, as soon as the jaws 8 and 9 come into contact the excess fluid delivered by the plunger 34 is returned to the supply 38 through the safety valve 43. It will be seen therefore that the strength of the spring 44 is so chosen that the valve 43 opens before the springs 22 (FIG. 3) start to become compressed. During the operation thus far described, the valve 43 also serves as a safety valve in the event that some extraneous element is inadvertently interposed between the jaws 8 and 9, since under such circumstances the fluid delivered by the plunger 34 is harmlessly returned through the valve 43 to the fluid supply without compelling the jaws 8 and 9 to move any closer together.

At the conclusion of the stroke of the plunger 34, the plunger 45 comes into action. As this plunger is moved into the cylinder 47 by the cam 56, the one-way valve 41 automatically seats itself as shown in FIG. 4 and the plunger 45 is thus allowed to deliver a predetermined additional amount of fluid under pressure through the conduit 42 and pipes 30 into the cylinders 18. This brings about an increase of pressure within the cylinders 18 just sufficient to overcome the force of the springs 22. As a result, the jaw 8 moves away from the flanges 21 and shifts rearwardly through the distance h. During this operation the cutting knife 12 moves with respect to the jaws into the recess 60 and thus cuts through the tubular packaging material held between the jaws.

As a result of the presence of the springs 22, the increasing pressure of the jaws 8 and 9 toward each other, brought about by the action of the plunger 45 in the cylinder 47, is not sudden, but gradual. It is only after the jaw 8 has moved through the distance h that the increasing fluid pressure within the cylinders 18 brings about a sudden and momentary increase in pressure between the jaws 8 and 9. The valve 48 serves to limit this pressure increase, because as soon as the pressure is great enough to overcome the tension of the spring 50 any additional fluid being delivered by the plunger is transmitted through the conduit 51 back to the supply 38. The strength of the spring is, therefore, so chosen that the valve 48 will open as soon as the desired sealing pressure between the jaws 8 and 9 has been reached.

The stroke of the plunger 45 in the cylinder 47 is completed before the downward movement of the jaws has been completed. Thereupon the plunger 45 returns to its outer position under the action of the compression spring 46 within the cylinder 47. As a result, the valve 48 closes, the fluid pressure within the conduit 42 falls, and the jaw 8 is returned, by the action of the springs 22, to a position wherein it bears against the flanges 21. At the conclusion of the downward movement of the jaws, the cam 54 permits the valve 52 to be opened. Under the action of the springs 27 the jaws 8 and 9 move apart, the fluid from the cylinders 18 flows back to the supply 38 through the valve 52 and conduit 53, and the operation is then ready to be repeated. Just prior to the commencement of another cycle, the cam 54 operates to reclose the valve 52.

During the operative stroke of the plunger 45, the withdrawal stroke of the plunger 34 takes place, to draw a new supply of fluid from the supply 38 into the cylinder 36 in readiness for the subsequent cycle of operation. Because the excess pressure valve 43 is positioned between the one-way valves 40 and 41 the pressure stroke of the plunger 45 delivers fluid only to the pipes 30 and no pressure fluid can return, during this period of time, to the supply 38.

The solenoid 55 is used when printed packaging material is being worked upon. As hereinbefore indicated, for this purpose the packaging machine is provided with an appropriate sensing apparatus, such as a photoelectric installation, responsive to predetermined markings located at spaced intervals along the length of packaging material. These markings might be spaced, for example, to correspond to the length of packages to be produced. Obviously, therefore, when one of these marks comes into the field of action of the sensing device, the latter, through appropriate circuitry, energizes the solenoid 55 and this draws the bellcrank lever 49 away from the valve 48 so that the latter opens. I The pressure within the conduit 42 diminishes immediately, and a corresponding reduction in pressure in the cylinders 18 brings about an immediate separation of the jaws 8 and 9 by virtue of the force of the springs 27.

The cylinder-piston arrangement of this invention for producing the transverse actuation of the sealing jaws can be employed with any of the three systems mentioned above for vertically positioning the tubular material, since the opening of the sealing jaws and hence the downward v movement of the tubular material can be optionally controlled either by valve 52 or valve 48. In addition, the cams 32, 56 and 54 are rotationally adjustable on the shaft 31 to alter the timed relation of operations, and the cams are removable from the shaft and replaceable by other differently shaped cams.

What is claimed is:

1. In a packaging machine including a pair of opposed jaws for forming transverse heat seals on a tube of heat scalable packaging material extending between the jaws in order to produce a series of individual sealed packages: means for moving said jaws toward each other to produce the seals and away from each other to release the packaging material, said means including at least one hydraulic cylinder-piston device, one of said jaws being secured to and movable with said cylinder and the other jaw being secured to and movable with said piston, said cylinder and piston being mounted for movement in opposite directions transverse to the axis of said tube in order to move said jaws toward each other upon introduction of fluid into said cylinder, a spring forming part of the securement between one of said jaws and the element of the cylinder-piston device to which it is secured so that said one jaw is yieldable with respect to said cylinder-piston device, a knife rigidly secured to said element of the cylinder-piston device but slidable with respect to said one jaw whereby after saidjaws come into engagement further relative movement between said cylinder and piston will cause said spring to yield to permit said knife to move between said jaws and sever said tube of packaging material, and means for introducing fiuid under pressure into said cylinder in two stages, one stage including a suction and pressure pump and the second stage including a simple pressure pump, and a single power source for driving both of said pumps.

2. In a packaging machine, the elements defined in claim 1 including an hydraulic circuit comprising said suction and pressure pump, said cylinder, and a reservoir for the hydraulic fiuid, a pressure-relief valve in said circuit between said pump and said reservoir, means for maintaining said valve closed during the movement of said jaws toward each other against the force of said resilient means for separating said jaws, but said lastnamed means permitting said valve to open before said spring yields. 7

3. In a packaging machine, theelements defined in claim 2 wherein said hydraulic circuitalso includes said simple pressure pump, and a valve for preventing the flow of fluid from said-latter pump to said. suction and pressure pump. and said pressure-relief valve.

4. In a packaging machine, the elements defined in claim 3 wherein the pressure of the fluid delivered by said simple pressure pump to said cylinder is high enough to cause compression of said spring thereby resulting in relative. movement between said knife and said jaws.

5. In a. packaging machine, the elements defined in claim 4 including an excess-pressure valve in said hydraulic circuit between said simple pressure pump and said 8. reservoir, means for maintaining said valve closed during compression of said spring, but said last-named means permitting said valve to open when a predetermined pressure between said jaws is reached.

6. In a packaging machine, the elements defined in claim 4 including an excess-pressure valve in said hydraulic circuit between said simple pressure pump and said reservoir, means for maintaining said valve closed during compression of said spring, and electromagnetic means responsive to markings on said packaging material for opening said valve.

7. In a packaging machine, the elements defined in claim 5 including a control valve in said hydraulic circuit between said cylinder and said reservoir, and means driven by said power source for maintaining said control valve closed during the movement of said jaws toward each other and for opening said control valve at a predetermined point in the machine cycle whereby said cylinder is exhausted and said resilient means is permitted to return said jaws to their initial separated condition.

8. In a packaging machine, the elements defined in claim 7 including a drive. shaft rotatedv by said power source, and a cam on said drive shaft allocated to each of said pumps and said control valve, said cams actuating said pumps and valve in timed relation, and said cams.

being rotatably adjustable on and removable fromsaid drive shaft in order to vary said timed relation.

References Cited by the Examiner UNITED STATES PATENTS 3,083,513 4/63 Cochrane 53182 FRANK E. BAILEY, Primary. Examiner.

BERNARD STICKNEY, Examiner. 

1. IN A PACKAGING MACHINE INCLUDING A PAIR OF OPPOSED JAWS FOR FORMING TRANSVERSE HEAT SEALS ON A TUBE OF HEAT SEALABLE PACKAGING MATERIAL EXTENDING BETWEEN THE JAWS IN ORDER TO PRODUCE A SERIES OF INDIVIDUAL SEALED PACKAGES: MEANS FOR MOVING SAID JAWS TOWARD EACH OTHER TO PRODUCE THE SEALS AND AWAY FROM EACH OTHER TO RELEASE THE PACKAGING MATERIAL, SAID MEANS INCLUDING AT LEAST ONE HYDRAULIC CYLINDER-PISTON DEVICE, ONE OF SAID JAWS BEING SECURED TO AND MOVABLE WITH SAID CYLINDER AND THE OTHER JAW BEING SECURED TO AND MOVABLE WITH SAID PISTON, SAID CYLINDER AND PISTON BEING MOUNTED FOR MOVEMENT IN OPPOSITE DIRECTIONS TRANSVERSE TO THE AXIS OF SAID TUBE IN ORDER TO MOVE SAID JAWS TOWARD EACH OTHER UPON INTRODUCTION OF FLUID INTO SAID CYLINDER, A SPRING FORMING PART OF THE SECUREMENT BETWEEN ONE OF SAID JAWS AND THE ELEMENT OF THE CYLINDER-PISTON DEVICE TO WHICH IT IS SECURED SO THAT SAID ONE JAW IS YIELDABLE WITH RESPECT TO SAID CYLINDER-PISTON DEVICE, A KNIFE RIGIDLY SECURED TO SAID ELEMENT OF THE CYLINDER-PISTON DEVICE BUT SLIDABLE WITH RESPECT TO SAID ONE JAW WHEREBY AFTER SAID JAWS COME INTO ENGAGEMENT FURTHER RELATIVE MOVEMENT BETWEEN SAID CYLINDER AND PISTON WILL CAUSE SAID SPRING TO YIELD TO PERMIT SAID KNIFE TO MOVE BETWEEN SAID JAWS AND SEVER SAID TUBE OF PACKAGING MATERIAL, AND MEANS FOR INTRODUCING FLUID UNDER PRESSURE INTO SAID CYLINDER IN TWO STAGES, ONE STAGE INCLUDING A SUCTION AND PRESSURE PUMP AND THE STAGE INCLUDING A SIMPLE PRESSURE PUMP, AND A SINGLE POWER SOURCE FOR DRIVING BOTH OF SAID PUMPS. 